Unable to login to email

I was teaching a guy to build a howtoforge perfect server setup using the debian squeeze with ISPconfig 3 and we've hit a snag. It appears as though everything is working, however, I'm unable to authenticate against the email server. I have included the main.cf for reference. Any questions, just let me know and thanks in advance for any suggestions.

Cheers!
ken

# See /usr/share/postfix/main.cf.dist for a commented, more complete version

# Debian specific: Specifying a file name will cause the first
# line of that file to be used as the name. The Debian default
# is /etc/mailname.
#myorigin = /etc/mailname

smtpd_banner = $myhostname ESMTP $mail_name (Debian/GNU)
biff = no

# appending .domain is the MUA's job.
append_dot_mydomain = no

# Uncomment the next line to generate "delayed mail" warnings
#delay_warning_time = 4h